This is a Phase 2 randomized, double-blind, placebo-controlled, multiple-dose, multicenter, parallel-group study to evaluate the analgesic activity of ATx08-001, a novel selective peroxisome proliferator-activated receptor modulator (SPPARM), in subjects with moderate-to-severe postherpetic neuralgia pain. Eligible subjects will be randomized to receive either placebo or Atx08-001. Study drug will be administered orally twice a day for 7 days. Subjects will be evaluated for neuropathic pain intensity at regular intervals over a 6 hour period on Day 1 following the first dose of study drug. They will then be discharged from the clinic and will complete diary assessments of pain severity twice a day at home. Subjects will be asked to return to the clinic on Day 8 to complete their last set of pain evaluations.